Hydrocarbon fluid, e.g. oil and natural gas, often are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a wellbore which penetrates the hydrocarbon-bearing formation. In many cases, the downhole environment presents harsh operating conditions, e.g. high temperatures, caustic chemicals, and cramped space constraints, with respect to downhole equipment. Additionally, many modern downhole tools require relatively close tolerances and numerous operating cycles to effectively and efficiently produce hydrocarbon fluid from the reservoir. The downhole conditions can cause scale to build up on surfaces of mating components and can impact the ability to control or fully operate the downhole tool in response to operational parameters or changing conditions at the well. Downhole scale also may lead to a reduction in productivity or performance due to obstructed flow passages.
As a result, various techniques are employed to inhibit formation of scale. Even so, scale and other particulates continue to cause equipment malfunctions and well productivity losses. One approach to inhibiting scale involves the metered injection of scale inhibiting chemicals through chemical injection lines extending from the surface. However, a significant drawback of this approach is an inefficient use of inhibitors because in situ conditions and scale creation progress is not precisely known and cannot be precisely determined. Therefore, operators typically prefer to err on the conservative side and over-inject chemicals rather than under-inject chemicals; and this over-injection leads to the inefficient use of inhibitors or it can cause adverse effects due to oversaturation of inhibitors in the produced fluids.
Even when the scale inhibitor chemicals are over-injected, many downhole situations and circumstances still allow for the continued growth of scale. Additionally, a further complication arises when downhole completions equipment is operated after remaining stagnant for many months or years because parts may have seized with scale.